The behavior you see above is the one you are going to get if you (incorrectly) have -m 4096 on the qemu-kvm command-line (the last node will be ignored by the OS because you are giving 1G for each node and the first four nodes are enough to cover the whole RAM).
If you use -m 5120, on the other hand, you should get the right behavior.
So, please show the full qemu-kvm command-line you used.

I confirm that bug is reproducible only if using the (incorrect) command-line:
/usr/libexec/qemu-kvm -m 4096 -smp 50,sockets=1,cores=50,threads=1 -numa node,mem=1024,cpus=0-9,nodeid=0 -numa node,mem=1024,cpus=10-19,nodeid=1 -numa node,mem=1024,cpus=20-29,nodeid=2 -numa node,mem=1024,cpus=30-48,nodeid=3 -numa node,mem=1024,cpus=49,nodeid=4 -vnc :0 -hda /var/lib/libvirt/images/rhel64.img
(it has 5 nodes of 1024MB each, but only 4096MB of RAM, so there's no enough RAM for all nodes)
The problem can't be reproduced if the command-line is set so that the amount of RAM is enough for all nodes:
/usr/libexec/qemu-kvm -m 4096 -smp 50,sockets=1,cores=50,threads=1 -numa node,mem=1024,cpus=0-9,nodeid=0 -numa node,mem=1024,cpus=10-19,nodeid=1 -numa node,mem=1024,cpus=20-29,nodeid=2 -numa node,mem=1024,cpus=30-48,nodeid=3 -numa node,mem=1024,cpus=49,nodeid=4 -vnc :0 -hda /var/lib/libvirt/images/rhel64.img
Moving back to ON_QA.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.
http://rhn.redhat.com/errata/RHBA-2013-0527.html

Note

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